Embodiments of the present invention relate to methods and apparatus for processing of biological material in an automated or semi-automated analysis instrument.
It is known to provide automated instruments for analysis of biological samples. For example human identification by deoxyribonucleic acid (DNA) analysis can be performed using a commercially available instrument sold by GE Healthcare and NetBio Inc, under the trade name DNAscan.
That instrument uses a microfluidic system to wash a cotton tipped swab head (like a cotton bud) attached to a plastic stem which is in turn attached to a plastic cap. The swab is dimensioned such that it fits in a sample receiving chamber in the microfluidic circuit and the plastic cap holds the swab head in place suspended above the bottom of the chamber on the stem in the circuit. The position in which the swab head is held is important because the head must not block the microfluidic circuit, but fluids in the circuit must be allowed immerse the head and reach the whole of the head to optimise the chances of collecting any sample material held on the head. The instrument is automatic, meaning that it processes the eluted sample by means of fluidic hardware and software without intervention. Other instruments are semi-automatic, meaning that some intervention may be required, but the principal analysis steps are carried out without intervention by hardware and software.
This known arrangement of sample swab is satisfactory for liquid phase biological samples that are capable of being transferred onto a cotton swab, but biological samples which may contain DNA are often only available in a solid phase form, e.g. dry, or in a form which cannot easily be transferred to a cotton swab. For example: fabrics; cigarette butts; chewing gum; body tissue; hair; and nail clippings could all contain DNA which could be recovered if the DNA were transferable onto a cotton swab, but that transfer is not guaranteed simply by wiping the cotton swab over the surface of those materials. Other such materials are readily apparent to a skilled addressee.
Where the sample cannot be transferred onto a swab, or where the transfer is not certain, then some other way is required to provide a sample to known microfluidic instruments which will not interfere with the operation of the instrument, but which can be collected easily, and held in the instrument at the correct position.
Embodiments of the present invention address the above problems.